Indicating mechanism for electric fuses or cut-outs.



N0. 854,327. PATBNTED MAY 21, 190? L. B. BUCHANAN. INDIGATING MEGHANSMFR ELECTRIC FUSES 0R GUT-OUTS.

APPLICATION FILED SEPT.14,1906.

'UNITED sTATEs Prieur orrren.'

LEONARD B. BUCHANAN, F WOBURN, MASSACHUSETTS.

Specification of Letters Patent.

Patented May 21, 1907.

Application-filed September 14, 1906. Serial No. 334,585.

sents a distinct article of manufacture that 5 can be sold separate fromthe fuse; which is adapted to be applied to a fuse whenever desired;which is adapted to be disposed externally on the fuse and therefore maybe readily applied thereto; which, when applied to Vthe fuse concealsthe fuse-wire which is provided. for operating the indicating-device;which may be applied to an existing fuse not now provid ed with anindicating-mechanism, or may be used to replace the indicatingmechanismof a blown fuse, in case the fuse is of the renewable type or is capableof being renewed or has been renewed; and which may be readily removedfrom the fuse to which it is applied, to be replaced by another, as inthe case of a blown fuse which is provided with my indicating-mechanism.

Figure l. shows in plan view an inclosed electric fuse provided with anindicatingmechanism embodying this invention. Fig. 2 is a longitudinalsection of theinclosed electric fuse and indicating-mechanism shown inFig. 1. Fig. -3 is a longitudinal section of the indicating-mechanism, aportion of the support and. fuse-wire being broken away. Fig. 4 is atransverse section of the indicatingmechanism shown in Fig. 3. Fig. 5 isa plan view of the indieating-mechanism. Fig. 6 is a side view of theindicating-mechanism. Figs. 7 and 8 are details to be referred to. Figs.9 and l0, respectively, show a plan view and longitudinal section of amodifiedform of indicating-mechanism embodying my invention.

.The electric fuse which is herein shown for the sake of illustrating myinvention is a familiar form of inclosed fuse of the cartridge type, yetI desire it to he understood that the indicating-mechanism embodying myinvention may be applied to other forms of 1nclosed electric fuse.

parts.

In the fuse shown, a represents the cylindrical tubular body of theshell or case and a', e the terminals tliereo1i,\vl1ich, are hereinshown as metallic end pieces or caps.

b is the main fuse wire which is contained. within the shell or case andwhich is herein shown as a strip of fusible metal, which is. connectedat its ends to the metallic terminals, thereby extending longitudinallythrough the shell or case. The shell or case is designed to be filledwith anhydrous plaster of paris, or any other of the finely divided orporous nonconducting refractory materials commonly used in iillinginclosed fuses.

The indioating-mechanism, two forms of which are herein shown for thesake of illustrating my invention, comprises an indicator, orindicatii'ig-device, actuating means therefor, a fuse strip or wire,hereinafter referred to as a'fuse-wire and a covering or support. Thecovering may be made of any nonconducting material capable of envelopingthe fuse-wire and withstanding ordinary wear and tear and the heat it islikely to meet, and as herein shown,` it consists of two The upper partis a strip or plate c of any suitable material, preferably a stif'ffiber capable of acting as a support, having at a point intermediate itslength a hold c of circular or other form,for the indicatingdevice; andsaid strip or plate cis made long enough to extend along the .outside ofthe shell or case and is adapted to be attached to the end caps af, ethereof by a screw or otherwise. The lower part of the covering ispreferably a piece of cloth f attached to the upper part of thecovering.

The indicating-device is located at the hole c in the upper part of thecovering, and,

as herein shown, said indicating-device and the means for actuating it,are substantially the same as shown in Letters Patent No. 801,467, datedOctober 10, 1905, being herein shown merely `for the sake ofillustrating one form of indicating-device which may be employed.

The indicating-device consists of a circular piece d of leather or othersuitable material adapted to be placed in the hole c', so as not toproject beyond the exterior line of the support, and to be retainedtherein by friction, yet, so far as my invention is concerned any otherform of indicating-device may be employed. The indicating-piece d isdesigned to be ejected from the hole by pressure pro- TOO IIO

duced in the indicating-compartment, due to the operation of theactuating means, as will be explained.

The fuse-wire b should be of small crosssectional area and of suitablemetal so as not to maintain an arc, as for instance, iine German silverwire or foil, preferably greatest in resistance under the hole c so asto heat most at that oint. This fuse-wire is extended along t e underside of the su port c, and is adapted to be connected witli theterminals of the fuse, so as to shunt the.

main fuse wire l), and being of high resistance will carry only atrivial part of the current until the mainy fuse wire is melted. Theshunt fuse-wire b crosses the hole c', and at said hole theindicating-compartment is formed, s'o that said Jfuse-wire extendsthrough said compartment.

t, t, represents two plates or pieces of material, such as cloth, placedone upon the other with the fuse-wire b between them, said plates orpieces being attached together and made large enough to more than coverthe hole c in the support c. The plates or pieces t, t are each formedwith a circular hole t2 through them, and the fuse-wire b crosses thishole, and said plates or pieces are so located with respect to the holec in the support yc that the hole t2 therethrough lies opposite saidhole c. These plates or pieces hold the fuse-wire b in theindicating-compartment.

rlhe actuating means for the indicatingdevice consists essentially of agas producing element, which, as herein shown, consists oi a plate ordisk e of any suitable material havmgupon one side of it a smallquantity of gas producing material e', as gun powder for instance, whichis laid thereon andrheld in place by adhesive material. The gas producinelement is placed against the under side o the plates or pieces t, t',being preferably adhesively attached thereto, and so located withrespect thereto that the gas producing material e lies opposite orenters the holes in said plates or pieces t, t. A piece of iiber 'n isdisposed next the gas producing element, so as to inclose the actuatingmeans for the indicating-device in a separate compartment. The lowerpart of the covering of the indicating-device serves to hold the partsassembled and to secure them to the upper part of the covering orsupport c and also to completely inclose `them in connection with theupper part of the covering. It is here shown as a comparatively largepiece of cloth f, which covers the piece or plate a and is adhesively orotherwise attached ,to the support c, and said piece f is made longenough to extend along and cover the portions of the fuse-wire whichwould otherwise be exposed, to thereby so confine said Jrusewire as toexclude the air from it, excepting in the indicating-compartment, sothat the tendency will be for it to heat and melt in theindioating-compartment, adjacent the actuating means for theindicating-device. To prevent the passage oi' any flame through the holec in the support c, when the fuse-wire 7) melts, a flame-resistingscreen s is employed, see Figs. 7 and 8, oi 'line mesh, which is madelarge enough to at least cover said. hole. This screen is placed next tothe support C, between .it and the means ior holding the fuse-wire, andthe opposite edges of said screen are or may be turned over the edges ofthe plates t, t, The screen s is formed with a central projection s of adiameter approximately as large as the hole c in the support, and saidproJection extends into said hole, as shown. The projection assists inholding the screen in place, and also serves as a stop for the indicatord, and also provides a cavity. to insure the production of a smallcompartment back of the indicator. When the lusewire li melts the gasproducing element explodes and the indicator d is ejected. ln lieu ofthis 'form of actuating means other forms of actuating means may beemployed, to operate the indicating-device shown, or other forms ofindicating-device. For instance, referring to Figs 9 and 10, amodiiication 'of the indicating-device is shown, which consists of aspring acting strip g applied to the outside of the supporting-plate c,Whichextends along on said plate in the direction of its length, and. isattached at one end to one of the terminal plates 0, while its other ori'ree end is bent downward and extends through the hole c in thesupportingplate, and its downwardly extended end g is formed with an eyethrough which the `fusewire b passes. The action of the spring actuatingstrip is for its free end to move away from the supporting-plate, asrepresented by dotted lines and when in such a position to indicate thatthe fuse has blown, but said strip is normally held by. the fuse-wireunder tension and against the supporting plate, as represented by fulllines. It will be seen that in this modification the spring action,inherent in the indicating-device, serves as the actuating means for it.

The ends of the Jfuse-wire b are designed to be electrically connectedwith the terminals a', a of the fuse, and to accomplish this resultterminal plates o, o are provided on the support c, which are hereinshown as pieces of sheet copper placed upon and bent around the ends ofthe support c, which are secured by solder or otherwise to the ends ofthe fusewire, and said terminal plates 0, 0 are respectively secured tothe terminal caps (1,, (1

- by screws .or otherwise, it being understoml that the support c ismade long enough to provide for thus enabling the terminal plates o, oto overlle the terminal caps.

IIO

sali-,sar

In lieu of electrically connecting the ends of the fuse-wire to theterminal caps a', a b y means of terminal plates 0, 0, as herein shown,my invention includes electrically connecting them thereto in any othermanner 5 and when terminal plates, such as 0, o, are employed theirshape or size may be varied.

The indicatingmechanism thus described is independent of the fuse andmay be sold as a separate article of manufacture; it is adapted to beapplied externally to the fuse; it is adapted to be so arranged on thefuse as to conceal the fuse-wire which is employed for operating theindicating-device; it is adapted to be appliedto a fuse not now providedwith an indicating-mechanism, or to be used to replace theindicating-mechanism of a blown fuse in case the fuse is of therenewable type, or is capable of being renewed or has been renewed 3 andfurthermore, it may be readily removed from a fuse to which it is'applied, so as to be replaced by another, as in the case of a blown fusewhich is provided with my external indicating-mechanism.

Having thus described my invention, what l claim as new and desire tosecure by Letters Patent is 1. An indicating-mechanism for an inclosedelectric fuse consisting of an indicatingdevice, actuating meanstherefor,` a fusewire, a support for said parts, and terminals thereonelectrically connected with said fuse wire and means for attaching thesupport to tlie outside of the shell or case of a fuse, and forconnecting thefuse-wire electrically with the terminals of said fuse,substantially as described.

2. lAn in(heating-mechanism adapted to be supported upon the.- exteriorof the shell or case of an inclosed electric fuse, comprising anindicating-device, actuating means therefor, a fuse-wire;y and means forelectrically connecting the opposite ends of said fusewire with theexterior of the terminals of said fuse, substantially as described.

3. An indicating-mechanism adapted to be supported upon the exterior ot'the shell or case of an inclosed electric fuse, comprising anindicating-device, actuating means therefor, a fuse-wire, andy means forelectrically connecting the opposite ends of said. fusewire with theexterior of the terminals of said fuse, and a support of insulatingmaterial for'said indicating-mechanism, substantially as described.

4. An indicating-mechanism adapted to be applied externally to aninclosed electric fuse, comprising an indicating-device, actuating meanstherefor, a fuse-wire having conducting terminals secured to its endsfor electrically connecting it with the exterior of the terminals of thefuse, a support for said parts, and means for attaching said support tothe exterior of the fuse, substantially as described.

5. An indicating-mechanism adapted to be applied externally to aninclosed electric fuse, comprising an indicating-device, actuating meanstherelior, a fuse-wire having terminal plates at its opposite ends forelectrically connecting it with the exterior of the terminals of thefuse, a support for said parts which is engaged by said terminal plates,and means for attaching said support to the exterior of the fuse,substantially as described.

6. An indicating-mechanism adapted to be applied externally to aninclosed electric fuse, comprising` an indicating-device, actuatingmeans therefor, a fuse-wire, means for holding said fuse-wire adjacentsaid actuating means, and a support for said parts, composed ofinsulating material and having conducting terminals which are adapted tobe attached to the kexterior of the terminals of the fuse, substantiallyas described.

7. A supporting-plate of insulating material having conducting terminalsadapted to be attached to the exterior of the terminals of an inclosedelectric fuse having a hole through it, an indicating-device at saidhole, actuating means for said indicating-device located back of it, butsupported bysaid plate, a fuse-wire also supported by said plate andlocated adjacent said actuating means, the opposite ends of which areconnected'with the terminals of the supportingplate, substantially asdescribed.

8. A supporting-plateof insulating material having conducting terminalsadapted to be attached to the exterior of the terminals of an inclosedelectric fuse, having a hole through it, an indicating-device at saidhole, actuating means for said indicating-device contained in acompartment back of said indicating-device, a fuse-wire extended throughsaid compartment and along the under side of said plate, the oppositeends of which are adapted to be connected with the terminals of theplate, substantially as described.

9. A supporting-plate of insulating material having conducting terminalsadapted to be attached to the exterior of the terminals of an inclosedelectric fuse, a fuse-wire extending along the under side of said plate,and connected at its ends to the tern'iinals of said plate, and anindicating-device borne by said plate for indicating the condition ofthe fuse, substantially as described.

10. An inclosed electric fuse having an auxiliary fuse-Wire external tothe casing thereof and removably connected to the exterior of the fuseterminals and an indicatingdevice, for indicating the condition ofthefuse-wire, substantially as described.

l 1. An inclosed electric fuse having an external shunt fuse-wire,removably connected IOO IOS

at its ends to the exterior of the fuse-terminals, means for coveringsaid fuse-Wire and an indicating-device, for indicating the condition ofthe fuse-Wire, substantially as described.

12. An inclosed electric fuse having exteriorly attached to itsterminals a shunt Yfuse-Wire, a supporting-plate for said shuntfuse-Wire, an indicating-device supported by said plate, and actuatingmeans therefor, substantially as described.

13. An inclosed electric fuse having removably attached to the exteriorthereof an indicating-mechanism consistingr of a fuse- Wire electricallyconnected to the terminals of the fuse and an indicating-device forindieating the condition thereof, substantially as described.

14. An inclosed electric fuse provided With an indicating-mechanismremovably attached to the exterior thereof consisting of a coveredJfuse-Wire, and an indicating-device for indicating the conditionthereof', sub- 'stantially as described.

15. An inclosed electric fuse of the cartridge type having removablyattached on the exterior thereof an indicating-mechanism consisting of acovered conductor of small cross sectional area, electrically attachedto the terminals of said cartridge fuse and an indicating-device forindicating the condition thereof, and actuating means for causing saidindicating-device to operate, substantially as described.

In testimony whereof, l have signed my naine to this Specification, inthe presence of tWo subscribing Witnesses.

LEONARD B. BUCHANAN.

